The Journal of Neurosurgery
The July 2013 edition of the Journal Of Neurosurgery, Volume 119, Issue 1 sees Dr James T Rutka as the newly appointed Editor-In-Chief of the journal having taken over from Dr John Jane Sr. after nearly 20 years in the post. This edition sees the publication of a number of articles in:
Functional Neurosurgery including (1) the long term outcomes from trans-middle temporal gyrus amygdalohippocampectomy and standard temporal lobectomy, (2) a retrospective analysis of outcomes following surgically treated drug resistant mesial temporal lobe epilepsy with correlation to histopathological findings and (3) the results of a pilot study regarding the implantation of deep brain stimulation electrodes into the lateral hypothalamic area for intractable obesity.
Skull base surgery such as (4) outcomes from sphenoid wing meningioma resections, (5) hearing preservation outcomes following the middle cranial fossa approach to vestibular schwannomas and (6) a review of the disparity in clinical managements of vestibular schwannomas throughout the United States of America.
Vascular surgery with (7) the much anticipated publication of the 3 year outcomes from the Barrow Ruptured Aneurysm Trial (BRAT), (8) mortality rates following surgery for intracranial dural AV fistulas and (9) a meta-analysis of the effect of the endothelin receptor antagonist Clazosentan on radiographic vasospasm and long-term morbidity.
Miscellaneous articles include (10) a comparison article from a single centre has been published comparing the accuracy of shunt catheter tip position between freehand, ultrasonic guidance and using stereotactic neuronavigation techniques.
The Barrow Ruptured Aneurysm Trial: 3 year results
Robert F. Spetzler, M.D., Cameron G. McDougall, M.D., Felipe C. Albuquerque, M.D., Joseph M. Zabramski, M.D., Nancy k. Hills, Ph.D., Shahram Partovi, M.D., Peter Nakaji, M.D., and Robert C. Wallace, M.D. J Neurosurg 119:146–157, 2013
Context: Following the publication of the ISAT trial in 2002, which showed an absolute risk reduction of 7.4% in patients undergoing endovascular coil embolisation compared to surgical clipping of ruptures intracranial aneurysms, there has been a marked increase in the use of endovascular techniques. The Barrow Ruptured Aneurysm Trial (BRAT) trial aimed to address a number of the concerns raised regarding the clinical suitability of the ISAT trial study population to the general population. These included the over representation of certain aneurysm types, bias from cross over and the exclusion of 80% of eligible aneurysms. Methods: The BRAT was a prospective randomised controlled study of all aneurysmal subarachnoid haemorrhage patients based on an intention to treat analysis. Of the 725 patients eligible for the study 472 consented for enrolment. There was a significant cross over between the endovascular coiling and surgical clipping arms with 38% of patients who were originally assigned to endovascular coiling undergoing surgical clipping. As such in total 280 patients underwent surgical clipping and only 128 patients underwent endovascular coiling. Patients who were originally assigned to the endovascular coiling arm but crossed over to the surgical clipping group were assessed based on the initial randomisation group and not the intervention they received to avoid the selection bias of cross over. Reasons for cross over from endovascular coiling to surgical clipping included patients who required intracerebral clot evacuation or had lesions in which endovascular intervention was considered disproportionately difficult. Cross over was not allowed based on patient grade or clinical condition. Poor outcome was defined as a mRS score >2 (signifying death or dependency).
Results: At 3 years 35.8% of patients who underwent surgical clipping and 30% of those assigned to coiling had a poor outcome. This difference of 5.8% was not statistically significant. The significant difference afforded by endovascular coiling from the BRAT one year outcome did not therefore translate to 3 year outcome. Patients initially randomised to endovascular coil intervention but crossed over the surgical clipping arm had statistically worse outcomes than those who were randomised to the endovascular coiling arm and received endovascular coiling. There was no statistical significance in the aneurysm sizes in the two intervention groups. Analysis of BRAT anterior circulation aneurysms revealed no difference at any time point between each treatment group, but posterior circulation aneurysms had 5 times better outcomes following endovascular coil embolisation. There was however a disproportionate number (18/21) of posterior inferior cerebellar artery aneurysms (PICA) who were assigned to surgical clipping. Within the 3 year follow up period 13% of the endovascular coil treated group required retreatment compared to 5% of the surgical clipping group (p0.01). Complete obliteration of the aneurysm at 3 years was 52% in the coiled group and 85% in the surgical clipping group (p<0.0001).
Conclusions: Three prospective studies have been undertaken to compare endovascular coiling to surgical clipping. These are the Finnish study, the ISAT and the BRAT. In all cases there was no difference in independent survival between the two groups at the longer term outcomes. There are major differences between the ISAT and BRAT cohorts with 22% of patients eligible for the ISAT being entered into the study compared to 65.1% in the BRAT. In addition the BRAT study cohort had a higher proportion of posterior circulation aneurysms and more patients with poorer grade subarachnoid haemorrhages. Coupled with the large proportion of patients who cross over from the endovascular coiling to the surgical clipping group there is a significant potential for bias in the ISAT. There are also higher rates of aneurysmal recurrence following endovascular coiling and longer follow-up durations are required to determine the morbidity/mortality related to this. As newer endovascular and surgical techniques, such as intraoperative angiography, emerge further studies will be required to evaluate this. There is no statistically significant difference between endovascular coiling and surgical clipping of anterior circulation aneusyms. Surgical clipping has the added advantage of better aneurysm occlusion, greater protection from rebleeding and less requirement for retreatment.
Vejay Vakharia MB BChir MA (Cantab) MRCS
Functional Neurosurgery including (1) the long term outcomes from trans-middle temporal gyrus amygdalohippocampectomy and standard temporal lobectomy, (2) a retrospective analysis of outcomes following surgically treated drug resistant mesial temporal lobe epilepsy with correlation to histopathological findings and (3) the results of a pilot study regarding the implantation of deep brain stimulation electrodes into the lateral hypothalamic area for intractable obesity.
Skull base surgery such as (4) outcomes from sphenoid wing meningioma resections, (5) hearing preservation outcomes following the middle cranial fossa approach to vestibular schwannomas and (6) a review of the disparity in clinical managements of vestibular schwannomas throughout the United States of America.
Vascular surgery with (7) the much anticipated publication of the 3 year outcomes from the Barrow Ruptured Aneurysm Trial (BRAT), (8) mortality rates following surgery for intracranial dural AV fistulas and (9) a meta-analysis of the effect of the endothelin receptor antagonist Clazosentan on radiographic vasospasm and long-term morbidity.
Miscellaneous articles include (10) a comparison article from a single centre has been published comparing the accuracy of shunt catheter tip position between freehand, ultrasonic guidance and using stereotactic neuronavigation techniques.
The Barrow Ruptured Aneurysm Trial: 3 year results
Robert F. Spetzler, M.D., Cameron G. McDougall, M.D., Felipe C. Albuquerque, M.D., Joseph M. Zabramski, M.D., Nancy k. Hills, Ph.D., Shahram Partovi, M.D., Peter Nakaji, M.D., and Robert C. Wallace, M.D. J Neurosurg 119:146–157, 2013
Context: Following the publication of the ISAT trial in 2002, which showed an absolute risk reduction of 7.4% in patients undergoing endovascular coil embolisation compared to surgical clipping of ruptures intracranial aneurysms, there has been a marked increase in the use of endovascular techniques. The Barrow Ruptured Aneurysm Trial (BRAT) trial aimed to address a number of the concerns raised regarding the clinical suitability of the ISAT trial study population to the general population. These included the over representation of certain aneurysm types, bias from cross over and the exclusion of 80% of eligible aneurysms. Methods: The BRAT was a prospective randomised controlled study of all aneurysmal subarachnoid haemorrhage patients based on an intention to treat analysis. Of the 725 patients eligible for the study 472 consented for enrolment. There was a significant cross over between the endovascular coiling and surgical clipping arms with 38% of patients who were originally assigned to endovascular coiling undergoing surgical clipping. As such in total 280 patients underwent surgical clipping and only 128 patients underwent endovascular coiling. Patients who were originally assigned to the endovascular coiling arm but crossed over to the surgical clipping group were assessed based on the initial randomisation group and not the intervention they received to avoid the selection bias of cross over. Reasons for cross over from endovascular coiling to surgical clipping included patients who required intracerebral clot evacuation or had lesions in which endovascular intervention was considered disproportionately difficult. Cross over was not allowed based on patient grade or clinical condition. Poor outcome was defined as a mRS score >2 (signifying death or dependency).
Results: At 3 years 35.8% of patients who underwent surgical clipping and 30% of those assigned to coiling had a poor outcome. This difference of 5.8% was not statistically significant. The significant difference afforded by endovascular coiling from the BRAT one year outcome did not therefore translate to 3 year outcome. Patients initially randomised to endovascular coil intervention but crossed over the surgical clipping arm had statistically worse outcomes than those who were randomised to the endovascular coiling arm and received endovascular coiling. There was no statistical significance in the aneurysm sizes in the two intervention groups. Analysis of BRAT anterior circulation aneurysms revealed no difference at any time point between each treatment group, but posterior circulation aneurysms had 5 times better outcomes following endovascular coil embolisation. There was however a disproportionate number (18/21) of posterior inferior cerebellar artery aneurysms (PICA) who were assigned to surgical clipping. Within the 3 year follow up period 13% of the endovascular coil treated group required retreatment compared to 5% of the surgical clipping group (p0.01). Complete obliteration of the aneurysm at 3 years was 52% in the coiled group and 85% in the surgical clipping group (p<0.0001).
Conclusions: Three prospective studies have been undertaken to compare endovascular coiling to surgical clipping. These are the Finnish study, the ISAT and the BRAT. In all cases there was no difference in independent survival between the two groups at the longer term outcomes. There are major differences between the ISAT and BRAT cohorts with 22% of patients eligible for the ISAT being entered into the study compared to 65.1% in the BRAT. In addition the BRAT study cohort had a higher proportion of posterior circulation aneurysms and more patients with poorer grade subarachnoid haemorrhages. Coupled with the large proportion of patients who cross over from the endovascular coiling to the surgical clipping group there is a significant potential for bias in the ISAT. There are also higher rates of aneurysmal recurrence following endovascular coiling and longer follow-up durations are required to determine the morbidity/mortality related to this. As newer endovascular and surgical techniques, such as intraoperative angiography, emerge further studies will be required to evaluate this. There is no statistically significant difference between endovascular coiling and surgical clipping of anterior circulation aneusyms. Surgical clipping has the added advantage of better aneurysm occlusion, greater protection from rebleeding and less requirement for retreatment.
Vejay Vakharia MB BChir MA (Cantab) MRCS
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